A.T. Fomenko, Double cover of the Klein bottle by torus
Pasha Zusmanovich

6/7TOPO Topology, winter semester 2025/2026

Monday 10:50-12:25   G302   ("Lectures" only)

LITERATURE
Main: Additional: All the books are available in electronic form in multiple places.          = available in the university library

A BRIEF SYNOPSIS
(Each class lasted approximately 1.5 hours; tutorials are running separately)

Class 1 September 22, 2025
Organizational details. The subject of topology. Definition of a topological space. Examples of topological spaces: trivial and discrete toplogy, topologies on 2- and 3-element sets, the standard topology on \(\mathbb R\). Number of topologies on a finite set.
([V], pp. xi-xii, 2, 11-12; Munkres, p.76).

Class 2 September 29, 2025
Base of a topology, examples. Any base of the standard topology on \(\mathbb R\) can be decreased. Criterion for a family of open sets to be a base ([V], p.16, 3.A).

Class 3 October 6, 2025
Further criteria for a family of subsets to be a base ([V], 3.B, 3.C). Finer and coarser topologies. Criterion for a topology to be coarser (Munkres, Lemma 13.3, also Theorem 1 here: pdf TeX ).
([V], pp.16-17; Munkres, p.81).

Class 4 October 13, 2025
The standard topology on \(\mathbb R^2\). Closed sets, definition of topology in terms of closed sets. Clopen sets. A parody of an episode from the movie "The Bunker" featuring clopen sets.
([V], pp.13-14,16-17).


A brief synopsis, videos, and homeworks from this course at the previous semesters


Created: Fri Oct 2 2020
Last modified: Mon Oct 13 2025 20:33:19 CEST